Beginnings of autism can be traced back to the second or third trimester of pregnancy, suggests a new discovery published in the New England Journal of Medicine.
Scientists analysed post-mortem brain tissue of 22 children with and without autism, all between two and 15 years of age, and used special techniques to examine specific types of neurons in the cortex.
They found numerous irregularities in the tissues of 90 per cent of autistic children, that were present in brain regions responsible for social and emotional communication and language. The dense patches were made of irregular-shaped neurons residing in the wrong cortical layers. 5 to 7 millimeters long, the patches were found in the frontal and temporal cortexes.
The researchers believe the irregularities developed long before birth as a result of the disruption in the development of cortical layers during the second and third trimester of pregnancy.
“If this new report of disorganised architecture in the brains of some children with autism is replicated, we can presume this reflects a process occurring long before birth,” said Dr Thomas Insel, director of the National Institute of Mental Health. “This reinforces the importance of early identification and intervention.”